diff -up cmsfs-1.1.8c/cmsfslst.c.orig cmsfs-1.1.8c/cmsfslst.c
--- cmsfs-1.1.8c/cmsfslst.c.orig	2020-08-19 09:47:36.459063820 +0000
+++ cmsfs-1.1.8c/cmsfslst.c	2020-08-19 09:47:45.619063820 +0000
@@ -49,7 +49,7 @@ int main(int argc,unsigned char *argv[])
       }
 
     /*  sanity check  */
-    if (*devname == 0x00)
+    if ((devname == NULL) || (*devname == 0x00))
       {
         (void) fprintf(stderr,"Please specify a CMS volume.\n");
         (void) fprintf(stderr,USAGE,argv[0]);